While not usually appreciated by the ordinarily observer, the vehicle chassis has undergone a substantial degree of change since early days of automobile design. Early frame design in, for example, the Ford Model T, comprised a pair of equally spaced apart and straight rails, a front cross member, and a rear cross member. The front transverse spring was attached to the front cross member and the rear transverse spring was attached to the rear cross member. The body rested on the frame rails while lips of the sheet metal components including the running board apron and, later in production, the rear fender fit between the frame rails and the body.
As vehicle technology advanced, the vehicle frame design became increasingly complex. Yet for many years standard approaches to chassis construction included the frame to which the front end and rear end were attached.
Over time, attention was increasingly drawn to vehicle safety, weight reduction and cost savings. While truck design has continued to rely on a frame as the core element of the chassis, passenger car design more commonly relies upon a front end assembly and a rear end assembly being attached to a body structure.
Some vehicles, for example British racing vehicles, provided a hybrid approach using a front frame structure attached to a fire wall while the rear assembly was suspended from the monocoque body.
Conventional front sub-assemblies are often made by stamping and welding together several individual frame components. Such arrangements provide the necessary structure but still often suffer from excess weight and expensive manufacturing costs. It is clear that vehicle front end designs have yet to take full advantage of weight reduction and reduced complexity by relying upon a reduced number of components.
Accordingly, there is a need for a front sub-assembly construction for a vehicle chassis that can provide safety and reduced weight for increased fuel economy without sacrificing rigidity and strength.